The present invention relates to a method and an apparatus for reducing power consumption of one or more processors in response to a failure condition affecting the processor or processors such as a thermal failure condition, and to a computer system incorporating such a method and/or apparatus.
In recent years, the processing power of processors has been increasing at a high rate. This increase in processing power has caused processors to heat up faster and to a higher temperature than previous processors. Therefore as the processing power has increased, a need has arisen for cooling the processor so that an overtemperature condition does not occur, since damage to the processor can occur if the temperature remains at too high of a level.
As the processing power of processors has increased and the need for maintaining the processor at a relatively low temperature has become important, new ways of maintaining a relatively low temperature of the processor have been implemented. For example, heat sinks have been attached directly on or near the processor to help dissipate some of the heat from the processor. Additionally, cooling fans have been used to blow air in the general vicinity of the processor or at the processor to help keep the processor from overheating. However, even when taking these measures, overtemperature problems can occur. Additionally, with the increase of processing power, the requirement for large heat sinks, blowers, cooling fans or other cooling mechanisms can cause size and expense problems, and these mechanisms are still sometimes unable to properly cool some processors even when these cooling mechanisms are operating at full efficiency.
In case of a failure, the temperature of the processor can rise to an overtemperature condition even if a cooling fan, a heat sink, or another cooling mechanism normally is able to maintain the desired temperature of the processor. For example, the cooling fan may fail for some reason (i.e., the speed of the cooling fan may be reduced or it may completely stop). In this case, the temperature of the processor can rise to a level which creates damage to the processor. Additionally, as processing power increases in current generation and future generation processors, additional measures for maintaining the temperature of the processor may become necessary. Therefore, a need has arisen for additional ways of maintaining the temperature of the processor below a predetermined level. These additional measures may be in addition to or in place of current implementations using cooling devices such as heat sinks and cooling fans.
In addition to using cooling devices such as heat sinks and cooling fans, other methods for ensuring that the temperature of a processor or processors does not become too high have previously been contemplated. For example, a failure signal corresponding to a reduced performance of a cooling mechanism such as a cooling fan can be produced when the cooling mechanism either fails or has some sort of other reduction in performance thereof. This signal is then used to completely shut down the processor, or provide a warning signal to the user of a personal computer or to a network manager, for example. However, if the signal is sent to the personal computer user or network manager (or other user) without turning off the processor, continued use of the processor could result in damage to the processor or other components of the system. Similarly, if the processor is shut off, a resulting reduction in performance of the processor or processors occurs during the time which the processor is shut off. If the processor is shut down, it is not operational until the failure is resolved. If such a processor is included in a uni-processor system, a system crash will occur and the entire system is shut down.
Additionally, other problems can occur with respect to signals sent to the processor relating to vital functions of the system which are not received by the processor during the time which the processor is turned off. For example, the time-out of vital functions may occur if the processor is shut off for too long of a time period. These signals relating to vital functions of the system are sent to the processor for only a specific length of time before a time-out of the signal occurs. If this time-out occurs, the processor does not receive the signals or perform any functions in response to these signals relating to vital functions of the system. For example, if a LAN (Local Area Network) network card is inserted and expecting a response from the processor, the network cards might drop clients if the processor does not respond to certain signals prior to a time-out of those signals (i.e., within a predetermined time period). Therefore, a reduction of the power of a processor while still performing some processing functions would be beneficial so that the processor is not damaged and so that no vital functions of the processor or system are inadvertently not performed.